The present invention relates to semiconductor devices and electronic control unit using the same. More particularly, this invention relates to a semiconductor device having metallic core layers and an electronic control unit using this device.
Prior known semiconductor devices include a device which has a wiring lead frame and a semiconductor circuit element as mounted on a die pad while using wire bonding techniques to connect together electrode portions of the semiconductor element and leads of the lead frame.
However, as semiconductor elements advance in quest for higher integration, semiconductor electrode portions rapidly increase in number, resulting in a semiconductor package increasing in pin number and size thereof. In addition, the advance in integration of circuit elements results in a likewise increase in power consumption per element area. This brings a need for a structure with isotropic heat releasability—namely, isothermal radiator structure—which employs a heat-radiating substrate.
Concerning equipment using semiconductor devices, this is under requirements for further miniaturization and higher packaging density while at the same time offering high performance and high functionality, a small-size semiconductor package with enhanced heat releasability is needed. Accordingly, in recent years, a high-density multiple-pin package having conductive balls, such as a ball grid array (BGA), chip scale package (CSP), flip chip (FC) or the like, has been developed. To improve the heat releasing performance, flip-chip mounting is applied to an interposer substrate with a heat sink being adhered to its upper part for heat radiation.
Additionally, JP-A-2003-46022 discloses therein an electronic device having a metal plate.
However, the above-noted prior art is faced with problems which follow.
In the structure having its lead frame and semiconductor element mounted on the die pad with the semiconductor element's electrode portions and the lead frame's leads being connected together by wire bonding, an attempt to mount a high-function semiconductor device(s) would result in an unwanted increase in size of a sealing resin material, a decrease in reliability after the mounting, and an increase in cost. In addition, a semiconductor device, such as a power supply or a driver or else which constitutes control circuitry, is a component that radiates a large amount of heat. In some cases, a plurality of such high heat-release components are needed. Thus, the application of this type of semiconductor device must have a limit.
On the other hand, in the case of using a high-density package such as BGA or CSP or else, its heating amount increases with an increase in integration and growth in high functionality. This calls for improvements in heat release performance. Additionally, due to the use of a large number of packages, a parts-mount substrate per se is required to decrease or “narrow” the layout pitch in conformity with BGA or CSP. This does not come without accompanying extra cost increase of the mount substrate, so this approach is incapable of offering successful applicability to multi-pin packages.
In case the semiconductor device of this type is employed for electronic control unit that is installed in severe environments, such as in land vehicles, when a narrow-pitch semiconductor package is used, solder bumps become smaller in diameter, resulting in the reliability being lowered at connection portions. Furthermore, in the case of a heat-radiating narrow-pitch semiconductor package being employed, additional design is required such as attachment of a heat sink plate. Some of the components involved fail to obtain the required heat release effect so that these are incapable of being mounted.
Regarding the structure as taught from JP-A-2003-46022, the heat releasability is insufficient. Additionally, its production cost poses problems.